"So that night we walked up and down the cemetery maybe five or six times and realised eventually that they had been stolen. It looked like the plaques had been pried off with a crow bar or something," Mitchell said.
Mitchell's uncle, Grant Nicoll, and her grandparents Patricia and Ian Nicoll were laid side by side at the cemetery inside a wall lined with memorial plaques.
Urns with the ashes of the Nicholls were behind the plaques and had gone missing along with the metal plates.
"Straight away we filed a report with the police, put a call in with the council just in case they had moved them or done something, but they hadn't," Mitchell said.
"Right now the family is trying to figure out what to do next. We just want the ashes back really, even anonymously because the plaques we can replace but there's not really any point in putting them back if there are no ashes."
Mitchell said her poppa had been her best friend and this week had been awful.
"No one should have to go through this, that is where they were laid to rest and for someone to just come in and vandalise that is the lowest of the low," she said.
"That's my family, the ashes have no sentimental meaning to them."
She said she can't think of a motive for the act, as no one in her family had any enemies and were loved by everybody.
Mitchell urges people to go and check their loved ones graves and memorial sites more often.
"That's something I'll probably regret for the rest of my life - not going up to check more often, because this could have happened anywhere from October last year to now," she said.
This isn't the first time the Paparoa Howick Cemetery has been targeted by vandals.
In August last year, the Herald reported that approximately 20 bronze plaques were stolen from the same cemetery.
Police confirmed they received a report that family ashes and plaques were stolen from Paparoa Cemetery sometime between October 2017 and 19 June 2018.
Police said it was a distressing time for the family.
In a statement police said: " We appeal to the person or people who took the ashes and plaques to do the right thing and return them to the cemetery. At the same time, if any scrap metal dealers come across the plaques, they should call police. "
If anyone has any knowledge of this incident, they are asked to contact their local station on 09 250 2800.
Alternatively, anyone can make an anonymous report to Crimestoppers on 0800 555 111.
Auckland Council's Manager Auckland Cemeteries Catherine Moore said they were concerned to hear that some plaques and ashes appeared to have gone missing from the cemetery.
"We take all issues like this very seriously, and have been in touch with the family conceded and are currently investigating," Moore said.
"We haven't had any other reports of missing or damaged plaques in the cemetery.
"If anyone has concerns or issues about a cemetery, we encourage them to get in touch with the council on 09 301 0101 or by calling their local cemetery team directly."